If I'm not wrong this buzzer needs over 100mA, not sure it's a good match for a CR2032 ?

I like how nothing slips past you! Yes, it's a pretty severe trade-off in exchange for its small size. So, I'll be using two CR2032's and make it run only in very short bursts. I honestly don't know how well or badly it will turn out.

I like how nothing slips past you! Yes, it's a pretty severe trade-off in exchange for its small size. So, I'll be using two CR2032's and make it run only in very short bursts. I honestly don't know how well or badly it will turn out.

I don't see anything to co trim such a high current on your board ? Maybe it's the reason the sound level is low on your other board, max current of the MCU pin is much lower than what the buzzer needs ?

I like how nothing slips past you! Yes, it's a pretty severe trade-off in exchange for its small size. So, I'll be using two CR2032's and make it run only in very short bursts. I honestly don't know how well or badly it will turn out.

I don't see anything to co trim such a high current on your board ? Maybe it's the reason the sound level is low on your other board, max current of the MCU pin is much lower than what the buzzer needs ?

Sorry phone rewriting what I type.
"Control".
MCU pins can't source that much current and I see no transistor on your board to do it ?
If you put a reserve capacitor big enough to supply 100+mA long enough to make some sound on the buzzer, will you not fry the pin ?

The present design uses a TPS22860 load switch to turn on and off the buzzer. I'm not trying to power the buzzer directly from one of the nRF52832 pins, because the current would be outside the maximum limits for the nRF52832 pin. I'm hoping the two CR2032's will give enough headroom that the voltage (after the LDO) will be stable.

I received the "holyiot" modules and they are really, really tiny. 2 attached together are exactly the same size than the 51822-04 module. WL-CSP package is very impressive: small, very thin and with a cool shinny surface.
This module has inductors for DC/DC mode, and pins .00 and .01 are mapped so it's possible to add low frequency crystal for Bluetooth mode.

Have you tried uploading anything to the HolyIOT modules? I've now tried on two different HolyIOT modules, both without success.

@nca78 It's a tricky module to solder (probably the most tricky of them all that I've tried so far), so to eliminate that concern on the second module I flipped it over and soldered wires directly to the four essential pads. That way I could visually confirm that it was soldered correctly. Still fails. So, just FYI.

I have the HolyIOT blinking an LED and receiving packets now. Range, as I suspected, is rather mediocre, but that's probably an inherent trade-off for its small size. For my purposes I don't think it will matter.

afaik (and I got a confirmation from Nordic too), there is no plan for other nrf52840 package than AQFN.
If you're searching for the ic, you'll have to use this footprint, which needs premium pcbs (micros vias, and multilayers for escaping routes and better plane).
It's also more tricky to solder than a fanstel BT840s and its bottom pins. BT840s edge pins are easy to solder sure but there are not so many. All others pins are on bottom as you know. Of course, it's the same for BT840, easier&better perf when using 4layers, but that can be done with 2layers (also explained in datasheet though).
From what I saw, others nrf52840 module sellers are going on same road, lot of tiny pads on bottom of the module, yes you can't do small things with big things, and there are lot of pins!

There is another thing to know. no arduino core for nrf52840 yet. Yes, it's possible to use radio, some pins too, but no spi, i2c etc. that's because it needs some code refactoring to handle multiple io ports (nrf52832 one io port, whereas 840 has two).

imho there are better mcu some silabs mcu for example.. but not arduino compatible, out of scope here, and lot of people would say, "not interested, it's two bucks more expensive", way of talking (not mine) as i don't remember the exact price .

@scalz To get smaller size, I expect we'll see modules with reduced pin counts for the 52840, just as we already do for the 52832. Have you heard anything about when final silicon for the 840 will be shipping?

@scalz To get smaller size, I expect we'll see modules with reduced pin counts for the 52840, just as we already do for the 52832. Have you heard anything about when final silicon for the 840 will be shipping?

yes sure. reduced IO pin counts.. and maybe even more reduced if they try to fit new features instead of IO (like usb etc). The above holyiot module example:

replace two IOs by USB pins.

keep same pinouts, but no USB, pity for a new interesting feature, but i can imagine not all people interested in it

need to enlarge the module for same pinout + usb pins

same module size and pinout, +usb, -> add bottom pads

I still don't get the point of a holyiot module, and chip antenna modules, when it's not for wearables though!

Complete waste of specs a 840 like that would be "funny", not much pins, with a chip ant..what would be the point then to buy a 840?? short ble5 range, no usb or just a few ios etc, yuk!
If you're after range, then take a look at the range comparison fanstel made. it's explicit how their different module design impact range. But if you don't need all the new bells&whistles of 840, then it may be smarter to use 832 or nrf24pa, and a good module, too bad to buy a module with degraded RF..

I asked Nordic two months ago, I don't think their eta changed. should be soon I imagine.

I measured the Fanstel BTC832X at maximum Tx, and it draws more current than I had thought: around 330ma. As you would expect, though, the range and coverage is excellent, even at 2mbps, and even for diminutive receivers like the HolyIOT.

For that reason, I think it generally beats the RFM69's performance, which IIRC consumes around 100ma at max Tx power, but has a max transmit speed of 300kbps. i.e. Total mah to transmit a payload should be less with the Fanstel BT832X.

Since the Fanstel's don't come with the low frequency crystal oscillators already installed, when it is worthwhile to install them? I'm blithely running off the built-in RC oscillator, and I'm not noticing problems.

Even with two CR2032's in series, I can't get 330ma out of them for very long, if at all, before internal resistance becomes severe and it plummets to 110ma or less. Nonetheless, at least some of the preliminary testing suggests that the initial burst may be good enough to extend the Tx range for long enough (100ms) to reliably wake a sleeping receiver node that sits outside the range of a non-amplified transmitter.

@neverdie The internal RC Osc will allow you to keep your BOM costs lower. However when using the Bluetooth Softdevice the Crystal will lower the power consumption as the BT window will be narrower.

Is the choice of RC osc or crystal of any consequence at all for Nordic's proprietary radio modes? For instance, I wasn't sure whether or not the cyrstal's greater accuracy might achieve a lower bit error rate at 2mbps.

Any suggestions how can I get serial debug messages out of the NRF52832 (Fanstel BT832)? I can upload the program over the SWD interface. I'm using a black magic probe with the Arduino NRF5 package on Windows 10. I know it works because the node shows up in my controller.

@neverdie
Do you define the pins in MyBoardNRF5? In MyBoadNRF5.cpp, I replaced the 0 in the first line with10, thinking this will map Arduino TX0 to P010. This did not seem to work. How do you map the TX0 pin?

Speaking of batteries, I found only one proper holder for holding two CR2032's in series:
It turns out you pretty much need the plastic carrier to guarantee that the edge of the button cell doesn't short out against the side of the metal holding bracket.

Footprint seems kinda large, at least for nodes intended to be small. It trades off length in order to get thin. In contrast, a CR123 is shorter (34.5mm), but thicker (17mm), but can deliver 1.5a continuous (which makes it very tempting for powering a PA):https://www.batteryjunction.com/energizer-cr123a.html
On the other hand, when you add the CR123 holder, the length may be comparable.

If you decide to try out the fanso, please do let us know how you like it.

@omemanti Suggest you check the Nordic datasheet on that rather than rely on the Ebyte documentation. IIRC, the DECT pins are not GPIO, but it's worth your double checking the nRF52 datasheet if it's important to you.

Has anyone succeeded in programming the WT51822-S4AT module (the cheapest and tiny nrf51822 module on AliExpress) using NRF52 DK ?
I pulled a lot of hair trying to find out what I did wrong with my board, I soldered an adapter to make sure I didn't have problems with faulty jumper wires etc, I reinstalled JLink and Nordic software, in the end I desoldered everything on my board, then the module itself to program it independantly. It always failed and JLink couldn't connect to it. I tried the other spare one I had, same result. I tried the one I'm sure I managed to program long ago with a jlink clone, always the same result.
Then I tried with an old nrf51822 module I bought long ago on AliExpress, and no problem !

Has anyone had similar problems ? Is there something special hardware wise that I should check ?

Has anyone succeeded in programming the WT51822-S4AT module (the cheapest and tiny nrf51822 module on AliExpress) using NRF52 DK ?

Yes. Haven't had a problem.

A couple things:

Are you powering the nRF51 module externally (separate from the nRF52DK)? It's highly advisable that you do, even though by random luck, you can sometimes succeed without it.

Especially for new, unprogrammed modules, you need to do a bulk erase at the beginning. I do this by the d00616 trick of saying "Burn bootloader" with a null bootloader. The burning bootloader process fails, as expected, but the side-effect is that it does a bulk-erase before failing.

I know you know these things, but sometimes we forget to do what we know.

@Nca78
Do you have the J-Link with only 4 pins? And if so, is the module a QFAAH0? In this konstalation I have the same problem, but with the J-Link V8 and ST-Link V2, the module can be programmed without any problem.

Especially for new, unprogrammed modules, you need to do a bulk erase at the beginning. I do this by the d00616 trick of saying "Burn bootloader" with a null bootloader. The burning bootloader process fails, as expected, but the side-effect is that it does a bulk-erase before failing.

if bulk erase is needed, then it means it was programmed a fresh new mcu is usually not programmed unless you ask for it to the manufacturer..

Like said above, it could be a problem with module, power issue, usb & cable, dupont cable, jlink, jlink setup, arduino core etc.

Are you powering the nRF51 module externally (separate from the nRF52DK)? It's highly advisable that you do, even though by random luck, you can sometimes succeed without it.

I was at the beginning, but after that I tried with power from the DK. I will try again with external power.

Especially for new, unprogrammed modules, you need to do a bulk erase at the beginning. I do this by the d00616 trick of saying "Burn bootloader" with a null bootloader. The burning bootloader process fails, as expected, but the side-effect is that it does a bulk-erase before failing.

I can't even reach that step, JLink can't establish the SWD connection so there's no way to erase the chip.

Do you have the J-Link with only 4 pins? And if so, is the module a QFAAH0? In this konstalation I have the same problem, but with the J-Link V8 and ST-Link V2, the module can be programmed without any problem.

@NeverDie@Nca78
then buy a fresh mcu on Mouser and you'll see by yourself
You don't get what I meant, I'm not talking about a specific module design, but in general. the mcu can be accessed by jlink no matter, else how would you program it in first place ..

@NeverDie@Nca78
then buy a fresh mcu on Mouser and you'll see by yourself etc
You don't get what I meant, I'm not talking about a specific module design, but in general. the mcu can be accessed by jlink no matter, else how would you program it in first place ..

Yes, but when there's a firmware it can be locked, so you must unlock it and erase it to remove softdevice and be able to write something.

@NeverDie@Nca78
then buy a fresh mcu on Mouser and you'll see by yourself etc
You don't get what I meant, I'm not talking about a specific module design, but in general. the mcu can be accessed by jlink no matter, else how would you program it in first place ..

Yes, but when there's a firmware it can be locked, so you must unlock it and erase it to remove softdevice and be able to write something.

are you sure it's locked? I thought neverdie suggested to erase it with jlink.
well, you should choose a better module than funky design modules.. just my opinion, for saving?? 2bucks!

well, you should choose a better module than funky design modules.. just my opinion, for saving?? 2bucks!

Well I was about to complain about my limited choice on Arrow (others ask 75$ shipping ), but after checking (again) I see that Arrow now has the Fanstel modules, so I have no reason to complain anymore
Too bad the BT832F is not in stock, but BT832 at 4.6$ is great, with the XE version in the gateway to compensate the lower range.

@scalz Well, what do you think he should use instead? Bare chips? That's not as easy to solder.

Frankly, I'm lazy answering to this question, same for technical stuff. sometimes I feel people miss what I'm trying to explain even if they haven't xp, and I keep repeating it... And the same for my designs, I'm wondering if it's worth the effort when i hear people trying to save 2-5bucks (not rewarding for time&money spent, not asking money btw), or want to reinvent cheaper&less quality variants (why not teamworking, not interested in infinite challenge, waste money&time) or complaining it's too hard to solder, did you read my many redondant advice in the forum, I don't handsolder tiny dfn, I reflow them, far far easier&quicker.
So that's settled, this is why I delayed my releases, until i change my mind, and I'm playing with software.
Sorry I don't want to look pedantic, not targeted against you especially, just tired

@scalz For comparison, I feel like the nRF24L01 is also pretty much a waste of time, given that better performing alternatives exist, and yet it's the most popular radio on the mysensors forum, possibly because it's so cheap and easy to wire up.
You have unusually high skills. A lot of people on this forum just want a list of throughole parts from Aliexpress that they can connect together using dupont wires. So, there's quite a range of skill levels. The biggest barrier I see is people not wanting to hand solder (let alone reflow) SMD parts onto a custom PCB. I think that's partly why the openhardware thing hasn't gotten much traction.

@scalz Well, what do you think he should use instead? Bare chips? That's not as easy to solder.

Frankly, I'm lazy answering to this question, same for technical stuff. sometimes I feel people miss what I'm trying to explain even if they haven't xp, and I keep repeating it... And the same for my designs, I'm wondering if it's worth the effort when i hear people trying to save 2-5bucks (not rewarding for time&money spent, not asking money btw), or want to reinvent cheaper&less quality variants (why not teamworking, not interested in infinite challenge, waste money&time) or complaining it's too hard to solder, did you read my many redondant advice in the forum, I don't handsolder tiny dfn, I reflow them, far far easier&quicker.
So that's settled, this is why I delayed my releases, until i change my mind, and I'm playing with software.
Sorry I don't want to look pedantic, not targeted against you especially, just tired

Reflow is nice and easy when you know how to do it, but not everyone has the space and money for it, and is willing to spend the necessary time to learn how to do it well. You need oven (that you usually need to modify), you need to buy stencils, you need to buy solder paste and keep it fresh in a separate fridge if you don't want to intoxicate your family when putting it in the kitchen fridge, you need to test/tune the process etc etc It's not for everyone. I tried, I have bought a hotplate (oven is too big and too expensive) and hot air gun, I ordered stencils to make some tests, but I can't get decent quality solder paste. Local shops sold me stuff that was way too old, when it comes from AliExpress it's low quality and it spent weeks at 30+ degrees, at Arrows it's either 50-100$ (that will end mostly wasted because I have no space for dedicated fridge), unavailable (maker paste) or "hazmat" so only sent by ground meaning not available for me. Life is hard

About the price I dont think everyone is ready to sacrifice quality to save a few $, I see people buying NModule PCBs at 25$ or more through openhardware.io for example, when they could buy much cheaper when ordering directly. I don't think those people will cry if components on a board cost 15-20$ instead of 10-15 but offer better range or reliability, lower power consumption etc.

About the "funky modules", yes they are not high quality but they still do the job (and way better than atmega + nrf24 clone), and when I first bought them I had no good alternative to get such a compact module, I would have bought them even if more expensive because compact modules on AliExpress or Ebay were either much bigger or with chip antenna, Arrow only had a Rigado module with LGA pins and other reputable shops have rip off shipping costs. Now I see Fanstel modules nearly as small, with better quality, FCC registration, low EMI etc etc at Arrow it would be stupid to continue, so of course I will not buy them anymore and redesign my board for the Fanstel. And if I make it public then I can provide a reliable source for the module, everyone can order from them with no shipping costs and 100% reliability. Way worth the few extra $.

And it's not always about reinventing things, it's about making things yourself and learning, too. I want to learn about ARM processors, bluetooth etc so to avoid having to learn anything at the same time I leave the reflowing, antenna tuning etc aside at the moment and use modules. If in the middle of this process I make a board that people with basic soldering skills can make themselves then how is it negative ? Those who take the MySensors hobby seriously will still favor your board because of the top notch quality and components used, there will also be a bunch of people interested in the complete board, but I think it's also great if people with lower technical skills but thirst for DIY can have something, too, even if "lower quality". Of course that won't be my "22" board, that's why I was thinking about a "33" version with more space to put bigger components (big SMDs or sensor breakout boards) and extension via MySX connector. Not sure if I will ever make it, and I hope it's not part of what is making you lose your motivation to release AEOS, because I'm waiting for it and it would be a good occasion to retry reflow soldering

I do think a lot of people really underestimate the toxicity of getting solder paste onto their hands. I always use disposable neoprene gloves when handling it, and try to throw away anything that comes into contact with it. You definitely don't want to run the risk of unintentionally ingesting that stuff. AFAIK, the neurotoxicity is permanent damage.

By the way, I never got to the point where reflow was "nice and easy" with tiny pad chips. But that's just me. Operator error, I'm sure. It ended up taking so long to get a good outcome that I just decided it wasn't worth the time. Maybe I'll revisit it at a future date.

Anyway, everyone has their limits. I mean reflowing the gazillion tiny components on a HopeRF module, for instance. That doesn't look easy to me, even if I knew what I was doing.

@scalz Anyway, it's great that you are doing it. You're an inspiration for us all.

@neverdie thank you for pointing to the power problem. I had one jumper left for my adapter to connect GND to GND and "as usual" it had a contact problem, I just replaced it and I can see the module in nRFgo Studio, even without external power.

@korttoma have you tried the code @NeverDie put together using the LPCOMP ? With a QFAAH0 (which I believe is the same version than QFABC0, but with 256K flash) he went down to something like 4µA.
From the document you link, anomaly 70, it will be necessary to add an extra wait of 36us after that line, it's strange that @NeverDie never had any problem with it. Or maybe I misunderstand the document

I don't remember. I've lately been using LoRa modules, plus getting distracted by CNC, so my nRF5 work has been on hold. I'm hoping that d00616 continues to work on the software though so that more than one nRF5 interrupt can be active at a time.

I tried to merge my sketch with the code provided by @NeverDie but I can not seem to get it to detect my button and I don't quite understand where I should attach my button that is on pin 28 to the interrupt thingie.

@nca78 it is ok, I think I will have to set up a test system with a different device with witch I can measure current consumption, attach serial logging and then try to fiddle with the code. I'm flying in the dark with this bluetooth beacon device since I cannot access any pins.

@neverdie thx. Why don't you have a capacitor between DEC4 to GND? I can see only 2 inductors, while Nordic power guidelines prescribe an LC filter between DCC and DEC, ie inductors and a capacitor. nrf52dk also has it.